Burt, 1955;® LaFond and Sastry, IQS?;'^ Ball and LaFond, 

 1964;® Tyler and Preisendorfer, 1962^). However, no 

 quantitative analysis of plankton taken in conjunction with 

 critical transparency measurements, such as is presented 

 in this report, has been found in the literature. 



The problem is difficult. Particles both living and 

 inanimate must be analyzed over a wide size range. Sampling 

 must be done frequently enough in time and space to correlate 

 with movements of water masses such as tides, currents, 

 vertical mixing, and turbulence originating at the air-sea 

 interface. For example, Burt, 19 55, ® dealing primarily 

 with inorganic particles with a median radius of 0,3 micron, 

 notes variations in extinction by a factor of 4 during a single 

 half-tidal cycle. Furthermore, turbid zones off the southern 

 California coast are related to internal waves (Ball and 

 LaFond, 1964®). Thus, plankton distribution can be just as 

 dynamic in time and space as internal waves. 



The relationship between the vertical distribution of 

 phytoplankton and thermal structure is well documented. 

 Gessner (1948), ^Johnson (1949),^^ and Sorokin (I96 0)" have 

 noted the highest concentration of phytoplankton in or above 

 the thermocline. Ball and LaFond (1964)® found the attenua- 

 tion of light to be associated with thermal gradients and 

 suggested phytoplankton as the causal factor. 



